This invention relates to an image display apparatus, and more particularly to an apparatus of the kind above described which is suitable for application to, for example, an apparatus for automated classification of blood cells so as to simultaneously display two or more different scenes such as a picture scene displaying an image of a blood sample and a character scene displaying data regarding the blood sample, so that an operator can observe the combined scenes on a single CRT.
A prior art apparatus for automated classification of blood cells is disclosed in U.S. Pat. No. 4,175,859. In such an apparatus, an operator required to observe not only a picture scene 1 displaying, for example, the state of a blood sample containing white blood cells 3 and red blood cells 4 as shown in FIG. 1a, but also a character scene 2 displaying data regarding the blood sample as shown in FIG. 1b. It has been a prior art practice that, for the purpose of observation of these plural scenes, an operator manipulates an input keyboard to change over between the scene shown in FIG. 1a and that shown in FIG. 1b. The manner of change-over between these scenes is disclosed in a catalog of "Hitachi's 806 Type Apparatus for Automated Classification of Blood Cells" published by Hitachi Ltd. in March, 1985. However, this prior art apparatus had a drawback that the operator could not simultaneously observe separate scenes. It will be very convenient for an operator of this kind of automated classification (analysis) apparatus when a picture scene displaying an image of a sample and a character scene displaying data regarding the sample can be simultaneously observed by the operator.